Progress on development of UV photocathodes for photon-counting applications at NASA GSFC

J. Stock*, G. Hilton, T. Norton, B. Woodgate, S. Aslam, M. Ulmer

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

25 Scopus citations


The development of high quantum efficiency photoemissive detectors is recognized as a significant advancement for astronomical missions requiring photon-counting detection. For solar-blind NUV detection, current missions (GALEX, STIS) using Cs 2Te detectors are limited to ∼10 % DQE. Emphasis in recent years has been to develop high QE (>50%) GaN and AlGaN photocathodes (among a few others) that can then be integrated into imaging detectors suitable for future UV missions. We report on progress we have made in developing GaN photocathodes and discuss our observations related to parameters that affect efficiency and stability, including intrinsic material properties, surface preparation, and the vacuum environment. We have achieved a QE in one case of 65% at 185 nm and are evaluating the stability of these high QEs. We also discuss plans for incorporating GaN photocathodes into imaging and non-imaging sealed devices in order to demonstrate long term stability.

Original languageEnglish (US)
Article number58980F
Pages (from-to)1-8
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2005
EventUV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XIV - San Diego, CA, United States
Duration: Aug 1 2005Aug 3 2005


  • GaN
  • Galium Nitride
  • Photocathode
  • Photon-counting
  • UV
  • Ultraviolet

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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